An ultraviolet sensor or detector absorbs UV radiation generally in the wavelength range between 100 nm to 400 nm and provides an output indicative of the sensed UV radiation. The UV spectrum can be subdivided into a number of different subbands, such as UVA, UVB and UVC. The wavelength (photon energy) of these subbands of the UV radiation range from 400 nm to 315 nm for UVA (3.1 eV to 3.94 eV), 315 nm to 280 nm for UVB (3.94 eV to 4.43 eV), and 280 nm to 100 nm for UVC (4.43 eV to 12.4 eV).
Typically, UV sensors are very costly because they utilize exotic and expensive wafer substrate materials, such as silicon carbide and sapphire wafers, which can be an order of magnitude more expensive than the silicon of which most semiconductors are typically manufactured.